"We believe it [the extension of hours] could be positive in terms of the number of hours spent at gaming tables by same-day travelers, and thus potentially for casino operator revenues," Barclays analysts wrote in a note.

The crossing between Macau and Hengqin Island will be open 24 hours a day, while the Gongbei Border Gate in Zhuhai will be open for two hours longer. The Zhuhai-Macau Cross-Border Industrial Park will be open to all Macau residents; currently, it's only open for employees of the industrial park.

The move could be heaven-sent for a casino market facing its first-ever year of annual revenue decline. In October, gaming revenue dropped 23 percent on year, the fifth straight month of declines and the steepest drop on record following two years of impressive growth.

An anti-corruption campaign in Beijing has significantly dampened gambling demand in the special administrative region among high rollers. VIP revenue made up 56 percent of total revenues in the third quarter, an all-time low.

A respite isn't coming anytime soon either, with Fitch Ratings projecting a 1 percent contraction for 2015 due to persistent weakness among VIPs, which is spilling over to the premium mass segment.

The increase in operating hours at the borders will definitely translate to more time spent at casino tables and acts as the first catalyst for Macau as visitors from the Guangdong province represent around 40 percent of total mainland visitation, said analysts at Citi Research in a note.

"The changes to the Henqin border would likely have a limited near-term impact, in our view, but could be positive in the long run as Hengqin's development projects are completed and potentially attract more residents and visitors to the area," Barclays added.

The average home price in the January-July period jumped to $12,635 (100,867 patacas) per square meter, a 22 percent increase from a year ago, according to official data. The city is expected to open over 17,000 hotel rooms over the next three years, but only 4,000 affordable homes for locals are in the pipeline for the same period, Reuters reported.

"We believe the progressive extension of border crossing hours could help alleviate Macau's housing shortage and housing price inflation problems, as some employees could choose to reside in China and cross the border to Macau for work," Barclays said.

Both Barclays and Citi interpret the decision as the Chinese government being supportive of Macau's long-term developments.

"Macau's 15th anniversary of handover to China falls on 20 December [two days after new rules take effect], which is when President Xi Jinping is expected to visit Macau. We believe this is his gift to the Special Administrative Region," Citi said.